Currently, users may use mobile devices such as photographing devices in daily life. Existing mobile devices may be equipped with one or more photographing functions. The one or more photographing functions of existing mobile devices grow fast and have developed from 0.2 mega pixels to 21 mega pixels, which become a selling point for mobile devices.
The photographing function of mobile devices may not only have a high definition, sharp focusing may also be an important part. Sharp and precise focusing may greatly impact image quality. Focusing is to adjust the distance between the lens of the mobile device and the image sensor so that the photographic subject is clearly imaged on the plane of the image sensor of the mobile device.
Temperature of mobile devices may increase due to the mobile devices working in long hours. Increased temperature of the mobile devices may broaden the range of focusing, so as to impact the focusing accuracy of the mobile devices.